Pressure bar support for veneer lathes



Nov. 17, 1953 Filed Aug. 24, 1950 J. T. LATIMER PRESSURE BAR SUPPORT FORVENEER LATHES 3 Sheets-Sheet l lav-E I 66 f INVENTOR.

w I k\\\\\\\\\\\ WEI/ll Ii/v55 2. 4.4770151 J. T. LATIMER PRESSURE BARSUPPORT FOR VENEER LATHES Nov. 17, 1953 Filed Aug. 24, 1950 3Sheets-Sheet 2 mmvrm d/VMIS I LIT/MEX B fflz ITTORNEYS Nov. 17, 1953 J.T. LATIMER PRESSURE BAR SUPPORT FOR VENEER LATHES 3 Sheets-Sheet 3 FiledAug. 24, 1950 INVENTOR. Jane; 7. L/rr/MER .BYi I flTTORA/EYS PatentedNov. 17, 1953 PRESSURE BAR SUPPORT FOR VENEER LATHES James T. Latimer,Birmingham, Ala., assignor to Jackson Industries Inc., a corporation ofAlabama Application August 24, 1950, Serial No. 181,295

6 Claims.

My present invention relates to an adjustable support for the pressurebar of veneer lathes and the like and has for an object the provision ofapparatus of the character designated by means of which the pressure barmay be withdrawn from the log, permitting the knife of the lathe to trueup the log prior to commencing the cutting of veneer therefrom, andwhich may also be provided with mechanism affording micrometricadjustment of the pressure bar relative to the Another object is toprovide a quick and positively acting means for moving the pressure bartoward and away from the log in combination with the above mentionedmicrometric adjusting means, permitting the pressure bar to be quicklyand accurately set to its work, the apparatus betag so arranged thatwithdrawing of the pressure bar does not disturb the setting of thepressure bar when the carriage is again moved toward the log.

A more specific object is to provide a fluid pressure cylinder formoving the pressure bar supporting means and hence the bar itself towardand from the log, and to operatively mount the micrometric bar adjustingmeans on the support, simplifying the apparatus and assuringpositiveness of operation.

Another object is to provide, in a veneer lathe or the like having apressure bar supporting carriage, rugged, accurate and simple means tomove and hold the carriage with the pressure bar thereof in engagementwith the log, such means being in the form of oppositely disposed wedgeblocks secured to a common axially movable member and cooperating withcomplementary stationary wedge blocks, together with means to move saidmember axially, whereby the pressure bar is engaged with a log in thelathe with very high, accurately determinable pressures which are equalthroughout its length.

In the art to which this invention relates it is well known that thequality of veneer cut in a lathe depends in great'measure upon thedegree of pressure with which the pressure bar engages the log. While sofar as I am aware, the exact values of these pressures are not known itis known that they are exceedingly high in the cutting of certainthicknesses of veneer from certain kinds of logs. In all instances theengaging pressure should be equally applied to the log at the correctpoint relative to the knife, and as stated, these pressures are for themost part very high. Heretofore, many forms of adjusting means for thepressure bar have been tried. Those with which I am familiar haveembodied threaded rods with gears for rotating them in synchronism,rotatable eccentrics and the like. Such apparatus has the disadvantages,among others, of inaccuracy, uneven application of pressure, excessivewear, high cost and susceptibility to mechanical failure due to the highstresses on the parts. Further, in the prior art apparatus the mechanismfor retracting the pressure bar has been generally unsatisfactory forsome of the reasons above mentioned.

Briefly, in my invention I mount the pressure bar carriage for slidingmovement on ways in very much the normal manner. To the rear side of thecarriage I fixedly mounted one or more heavy, double acting fluidpressure cylinders. The piston rod or rods of the cylinders carrymembers reciprocably mounted in supporting housings, the members havinga tapered side. Cooperating with the tapered sides of the members arecomplementarily tapered wedges, keyed to an axially movable shaft. Theshaft is provided with a threaded portion, preferably, though notnecessarily near its longitudinal center and carrying an operating nutheld against axial movement by a suitable mounting. When pressure isadmitted to the forward side of the piston, the cylinder and hence thepressure bar support move toward the,

log until the piston comes chock-a-block in the cylinder. By moving theshaft axially I am enabled to move the pressure bar toward or from thelog an infinitely small or an appreciable amount depending solely uponthe taper of the wedges andthe total axial movement of the shaft. Thepressure bar carriage may be moved away from the log by admittingpressure to the other ends of the cylinders, this being accomplishedwithout in any way interfering with the micrometric adjustment of thepressure bar mechanism.

Apparatus embodying the features of my invention is shown in theaccompanying drawing forminga part of this application in which:

Fig. 1 is a sectional plan view, somewhat diagrammatic and with certainparts broken away and showing a veneer lathe embodying my invention;

Fig. 2 is a sectional view taken generally along line II--II of Fig. 1;

Fig. 3 is a detail sectional view taken generally along line IIIIII ofFig. 1;

Fig. 4 is a sectional view taken along line IV.IV of Fi 1; Fig. 5 is asectional view taken along lineV--V of Fig. 1;

Fig. 6 is a fragmental sectional exploded perspective view showing theaxially movable shaft, certain of the supporting bearing blocks thereforand one of the wedges and cooperating blocks;

Fig. '7 is an enlarged detailed sectional view taken generally alongline VII-VII of Fig. 1;

Fig. 8 is a fragmental plan view of the pressure bar indicator dial andpointer;

Fig. 9 is a view corresponding generally to Fig. 1 and showing amodified form of my invention;.

Fig. 10 is a sectional view taken generally along line x-x of Fig. 9;and,

Fig. 11 is an elevational view of one of the ad justing shims which maybe employed with the invention shown in Figs. 9 and 10.

Referring now to the drawings for a better uhderstanding of my inventionand more particularly to Figs. 1 to 8 inclusive, I show'my ir'iv'entionassociated with a lathe embodying a supporting manner understood, thecarriage l2 slides toward a and from a log l3 mounted in the lathecenters indicated at I4 and It in Fig. 1. The log is driven by means ofa chain I 'I or the like from a suitable motor or the'like, not shown.

The main carriage is moved toward and from the log by means of feedscrews I9 and 2|, each carrying a bevel gear 22 on one end. The gears 22mesh with similar gears 23 carried on a shaft 24 which may be driventhrough a sprocket or the like 26 from any suitable source of power, notshown. As iscustomary, the maincarriage carries 'at its front the veneercutting knife 21 which is supported in the knife support ing mechanismindicated generally by the numeral 33. The depth of cut for the lathe isdetermined by the infeed motion produced by the feedscr'ews 19 and 2|.

Slida'bly mounted in guides 28 and 29 in the main carriage I2 areprojections 3| and 32 in the form of heavy plates. The plates 3| and32form a part of the pressure bar carriage indicated generally bythenumeral 33, and the apparatus is so arranged that the pressure'barcarriage is movable toward and from the log l3.

The carriage 33 comprises a main base plate having welded or otherwisesecured thereto upstanding vertically disposed plates 36 and-31. Theplate 36 may carry a rearwardly sloping reinforcing and strengtheningplate 38, while the plate 31 may carry a reinforcing plate 39 generallyparallel to the plate 34. The plates 38''38 are connected to the plate31 at intervals by vertically disposed plates 4|.

Mounted at the front of the carriage 33, namely at the side thereofadjacent the log l3, is'th'e' Plf ure bar 32. The pressure bar 42 may bein any of the several forms known in the art, ineluding the plain,rounded edge solid type. However, for the purpose of illustration I showthe same as embodying the bar "with theengaging roller 43 suitablymounted for rotation in elon'- gated bearings carried in the bar '42.The bar 42 maybe held in adjusted position by means of 'a plurality ofsleeves 44' screwed through the plate 36. Studs 43 pass through thesleeves N, and a" lock nut "serves to lock the sleeves against rotation.The bar 42 and hence the roller '33 are adjusted outwardly of the plate36, hence to correctly align the same relative to the axis'of the'log.It will be understoodthat'there area 4 large number of the sleeves 44and studs 48 pro vided so that the thrust is adequately transmitted tothe carriage 33. These sleeves are accessible for adjustment through theresulting openings between the plates 4|.

Mounted on the rear side of the plate member 31 of the carriage 33 andwith their axes parallel to the direction of movement of the carriage 33are two heavy duty, double acting fluid pressure cylinders 48 and 49.The cylinders embody the usual pistons 5| and 52, heavy piston rods 38and. and the usual seal means in the form of glands 56 and 51. For areason later to appear the outer ends of the piston rods are reducedandthrea'd'ed' as indicated at 53 and i3. Fluid may be admitted toeither end of the pistons through li'nes BI and 62.

on heavybrackets 63 upstanding from the rear side of the main carriagel2 and forming parts of the main carriage is a cross frame comprisingparallel plates 64 and 68 connected by a base plate 31'. Mountedadjacent each end of the framejust mentioned, and secured to the plate31- thereof by means of bolts 83 are bearing blocksll and 12 forsupporting the end of a longitudinally movable wedge carryin member I3.In view of the fact that the mechanisms now to be described and whichsupports each end of the member 13 are duplicates. a description of onewiii-suflice for both. As best shown in Fig. 6, the blocks II areprovided with a U-shaped opening H! for receiving the end of the memberI3, which preferably is a square shaft. The blocks H are held to thebase plate 31 by means of the bolts 69.

Disposed to cooperate with the blocks It in holding the member 13therein are L-shap'ed blocks or caps'lljwhich fit against the slottedoutstanding legsof the blocks H, and are held thereto'by means'ofcountersunk bolts 16. The members H and their respective caps I4 arespaced apart to provide aligned openings 11 and 18. Slidably fitting inthe openings 11 18' a 'U- shaped block 19 having vertically elongatednotches 8| in the edges of the base section and with the legs thereofparallel to the plates 6'4 and 66. Keyed to the base of the block 13 bymeans of projections 32 fitting in the notches BI. is a block 83 havinga tapering front face 84. .Flttingnext adjacent the face 34 is a wedgeblock 86 'ha'vihga 'complementarily tapered face 31. The block'ti'iskeyed' to the square shaft 13 by means of a projection-'33 disposedto fit in a slot 89"in'the shaft. The U-shaped block 19 and the shaftmay slide against wear plates 19a and 13b.

' on" the opposite side of the shaft '13 are provided identicalwedge'blocks 36, similarly keyed to the opposite face of the'shaft 113and another of thetaper'blocks '83. The forwardmosttaper block 83 iskeyedto a; cap 9i joining theforward ends of the legs of block 19', andsecured thereto-by screws 30. The U-shaped blocks" togetherwiththe'caps' 9"! thus 'forin hoiisings surrounding the endsofthe shaft 13'.The cap 3 I is provided with a' threaded hole 92' for receiving thethreaded reducedehdof the'pistonrodLock nuts 03 secure tlgg caps inadj'u'sted position on the piston r s.

It will "be rioteclthatthe taper blocks and wedg'e'blocks at each end ofthe shaft 13 slope in the samedirection. Thus, whentheshaft "is moved:axially to the i'IEht, the -U-shaped blocks Ts'and' theireaps 8iconstituting housings, move outwardly, thus movin'g'the entire pressure.har carriage '33 thrcughtnepiston rods 33 and,

all as will more fully appear. The mechanism for shifting the shaft I3axially will now be described.

Mounted to the forward face of the plate 61 by means of bolts 94 is aU-shaped nut housing member 99. The ends of the forward legs of thehousing 96 are provided with aligned semi-circular openings 91 forreceiving the reduced end 98 of a split nut 99. The nut 99 fits on athreaded centrally disposed section 13a of the shaft I3 and the halvesthereof are secured together by countersunk bolts, not shown. The nut 99is also provided with a sprocket IOI, driven by a chain I02, in turndriven by a sprocket I03. The sprocket I03 is carried on the end of anoutput shaft I94 of a gear box I06 to which is connected a reversibleelectric motor I01. The motor and gear box may conveniently be mountedon the plate member 64 as shown more clearly in Fig. 4. It will be notedthat the reduced ends 98 of the nut are shouldered. Nut retaining capsI95 fit about the reduced ends of the nut, and are held to the member 96by bolts I00.

For convenience in determining the setting or axial position of theshaft I3 I may provide the indicator mechanism therefor shown in Figs. 7and 8. To the top of the shaft I3 I secure, by means of a bolt I08, aplate I09 having gear teeth I I cut in one edge. Mounted in a suitablebearing Ii I in the frame plate member 64 is a shaft II2. A small gearH3 is fixed to the shaft H2 and meshes with the teeth I I 0.

Mounted on top of the plate 64 is a pointer I I 4. Fixed to theprojecting upper end of the shaft is a rotatable disc H9 which is laidoff on its upper face by means of the lines II! from a zero point asindicated in Fig. 8. By reference to the disc I I6 and the pointer H4the axial position of the shaft I3 may be determined.

Fluid under pressure may be admitted by a four-Way valve IIS selectivelyto the lines GI and 92. In the manner understood for such valves. whenpressure is admitted from a source, not shown, through the line IIEI tothe cylinders through line BI, fluid drains back to the reservoir, notshown, through a line I2I, and vice versa when pressure is admitted tothe line 62. In order to assure that there are no fluctuations in thepressure within the cylinders 48 and 49 when the lathe is in operation Imay provide a pressure line I22 leading from a source of fluid underpressure not shown, to the line 62. Also, I may insert a check valve I23in the line I22.

From the foregoing the method of constructing and using my improvedapparatus as so far described may now be explained and understood. Whena log I3 is first placed in the lathe it is necessary to trim off theprojecting limbs, knots and the like preparatory to commencing theveneer cutting operation. In order for the knife to properly act uponthe log to true it up, it is necessary to withdraw the pressure bar 42.I accomplish this by admitting fluid under pressure through the valveII8 to the pistons 48 and 49 through the line 6|. This causes thepressure bar carriage 33 to move to the right to the position shown inFig. 2 of the drawing. The pressure bar in this position is retractedaway from the log. After the knife trues up the log, fluid is admittedto the cylinders 48 and 49 through the line 62, moving the pressure barcarriage 33 to the left. The pressure is maintained in the line 92during the veneer cutting operation. The pressure bar is now adjusted tothe correct pressure against the log by energizing the motor I01,

rotating the nut 99, which as will be remembered is held against axialmovement in the member 96. Rotation of the nut in a given directionmoves the shaft I3 axially. If it is desired to increase the pressure onthe pressure bar against the log the shaft I3 is moved to the left asviewed in Fig. l by energizing the motor I0'I'to drive the nut in thedirection desired. It will be apparent that tremendous pressures betweenthe pressure bar and log can be developed because of the wedgearrangement shown. Further, when the pressure is set, the entire maincarriage I2 moves inwardly, thus cutting a continuous sheet of veneerfrom the log, and in nowise disturbs the amount of pressure initiallyset. If for any reason it is necessary to back ofl. the carriage 33 andagain engage the pressure bar with the log this may be accomplishedwithout disturbing the inicrometric pressure bar adjustment since thehydraulic cylinder acts independently of the micrometric adjustingmeans.

It will also be seen that the nuts 93 and threaded ends of the pistonrods afford means for adjusting and truing up the entire pressure barcarriage so that the pressure bar is parallel to the axis of the log,namely, parallel to the lathe centers. By means of the threaded sleeves19 and lock nuts til together with the studs 46 I effectively eliminatebowing of the pressure bar by supporting the same at a number of pointsthroughout its length, thus to transmit the pressure back to thepressure bar carriage.

Referring now particularly to Figs. 9, 10 and 11, I show a modified formof my invention in which the wedge mechanism may be eliminated. Themodification shown is particularly advantageous for use in smallerveneer lathes, and is somewhat less expensive to build.

As shown, the pressure bar carriage 33a and main carriage I20. aresubstantially identical with the one already described as are the infeedscrews therefor. Instead of using two of the cylinders 48 and 49, I usea single cylinder 43a having a piston I24 and a piston rod I26. Theouter end of the piston rod is pivotally connected by a pin IZEc to aclevis l2! carried by the base plate member 61a. Fluid under pressuremay be admitted through the four-way valve II8a to either side of thepiston through the lines 6Ia and 92a. Also, I may provide the auxiliarypressure line i22a and the check valve therefor I23a.

In order to limit the pressure with which the pressure bar 42a engagesthe log, I provide a pair of rearwardly extending bolts I28. The outerends of the bolts are threaded as indicated at I29 and the bolts passthrough enlarged holes I3I in the base plate member 67a. On the threadedends of the rods I provide lock nuts I30 and a washer I32. If desired, Imay insert shims I33 between the washers I32 and the frame member 61a.These shims may be U-shaped as illustrated in Fig. 11 and may be madeaccurately to desired thicknesses.

From the foregoing it will be seen that when pressure is applied to thecylinder 48a the car riage 99a moves forwardly until its forward motionis arrested by the bolts I28 reaching the limit of their travel asdetermined by the setting of the nuts I30. Since the piston rod I26 ispivotally mounted to the plate 61a there is no bending action on thepiston rod during the motion of the carriage. The pressure of thepressure bar roller 43:: thus may easily be determined by properlyadjusting the nuts I 30.

From the foregoing it will be apparent that I awe have devised animproved adjustable pressure bar mechanism for veneer lathes. Witheither form of my invention it will be understood that the cylinders areof sufficient size and the pressures therein are sufficiently great toassure the holding of the pressure bar to its work within any normalrange of setting either made by the wedge mechanism or permitted byadjusting the nuts I30. With either form of the invention it will beseen that the pressure bar may be retracted easily and quickly from itswork when it is necessary to do so, especially when truing up a new log.It will further be apparent that both forms of the invention areentirely practical and simple of construction and that they lendthemselves to installation on existing veneer lathes without majorchange in the lathe.

While I have shown my invention in but two forms, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various other changes and modifications without departing from thespirit thereof, and I desire, therefore, that only such limitationsshall be placed thereupon as are specifically set forth in the appendedclaims.

What I claim is:

1. In a veneer'lathe having a main frame and a pressure bar carriageslidably mounted for movement relative to the main frame toward and fromthe lathe centers, the improvement comprising an elongated membermounted for axial movement relative to the main frame rearwardly of thepressure bar carriage and held against lateral movement toward and fromthe pressure bar carriage, wedges carried by the member ad- Jacent eachend thereof, a housing for each of the wedges carrying complementarilytapered surfaces engaging said wedges, means mounting the housings formovement toward and from the pressurebar carriage and holding themagainst movement in other directions, connections between the housingsand the pressure bar carriage, and means to shift the member axially ineither direction whereby the Wedges move the pressure bar carriagetoward the lathe centers when the membermoves in one direction and awayfrom the centers when the member moves inthe other direction.

2. Apparatus as deflned in claim 1 in which the axially movable memberis a square shaft,

and in which the means to move the same comprises a rounded and threadedsection on the shaft, a nut on the threaded section, means holding thenut against axial movement, and means to rotate the nut.

3. Apparatus as defined in claim 1 in which the connection between thehousing and pressure bar carriage is in the form of elongatable andcontractible mechanism.

4. In-a veneer lathe of the type having a main frame with a maincarriage slidably mounted thereon for movement toward and from the lathecenters and a pressure bar carriage slidably mounted on the maincarriage for movement relative thereto toward and from the centers, theimprovements comprising a shaft mounted for axial movement on the maincarriage rearwardly of the pressure bar carriage and held againstmovement toward and from the pressure bar carriage, housings surroundingthe shaft adjacent its ends, means mounting the housings for slidingmovement toward and from the pressure bar carriage, wedge meansinterposed between the front and rear sides of the shaft and thehousings effective upon axial movement of the shaft to slide thehousings toward or from the pressure bar carriage, power driven meansfor moving the shaft axially, fluid pressure cylinders embodying pistonsand piston rods operatively interposed between the housings and the rearof the pressure bar carriage, and means to admit fluid under pressureselectively to opposite ends of the cylinders.

5. Apparatus as defined in claim 4 in which there is provided indicatormeans for determining the relative outward positions of said housingsfrom the portion of the main carriage with which said housings areassociated.

6. Apparatus as defined in claim 5 in which said indicator mechanismcomprises a rotatable shaft, a gear on one end of the shaft, a rackcarried by the axially movable shaft and meshing with said gear, a dialacUacent the other end of the shaft, and a pointer adjacent the dialcarried by the main frame of the lathe.

JAMES T. LATIMER.

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